Israel Halperin, a brilliant mathematics professor who successfully faced down espionage charges in Canada in 1946 and 1947 during the Gouzenko Affair and became an influential campaigner for human rights, died March 8, 2007. He was 96.
Following graduation from the University of Toronto, Halperin earned a Ph.D. in mathematics from Princeton in 1936, under Professor John von Neumann. He returned to Canada in 1939 as an assistant professor at Queens University.
After military service, he returned to Queens University, but in early 1946, he endured 13 months of detention, spy accusations, and a trial before the Canadian Government dropped the charges. It took another 14 months for Halperin to be restored to his university position. Among the testimonials sent on Halperin's behalf was a letter from the Institute of Advanced Study in Princeton signed by Albert Einstein and 11 others.
In 1976, Halperin retired from the University of Toronto. He is credited with introducing operator algebras to Canada and completing two substantial manuscripts left by the great von Neumann.
In 1999, the New York Academy of Sciences gave him its Pagels Award for advancing the human rights of scientists around the world.
Halperin is survived by his wife, Mary, whom he married in 1940, and their four children.